Technical Field
The present disclosure relates to a method of manufacturing an optical waveguide device and a laser processing apparatus.
Related Art
An optical waveguide device has been known in which an optical waveguide for guiding an optical signal is formed on a wiring board that handles an electric signal. The optical waveguide device is an optoelectronic composite board, and can transmit a high-speed signal in form of the optical signal so as to make up for a limit of a transmission speed of the electric signal.
An optical path conversion mirror is arranged at an end of the optical waveguide, and an optical element is mounted on the wiring board so that it is optically coupled with the optical path conversion mirror of the optical waveguide.
According to an example of a method of manufacturing the optical waveguide, a lower cladding layer, a core layer and an upper cladding layer are first sequentially formed on a substrate. Then, the laser is used to process the upper cladding layer and the core layer, so that a recess portion having an inclined surface of 45° relative to a light propagation direction is formed.
The light, which propagates through the core layer, is reflected in a vertical direction at an air interface of the inclined surface in the recess portion and an optical path thereof is thus converted.
[Patent Document 1] Japanese Patent Application Publication No. Hei 6-3539A
[Patent Document 2] Japanese Patent Application Publication No. 2000-117465A
[Patent Document 3] Japanese Patent Application Publication No. 2012-13819A
In order to form the recess portion having the inclined surface in the optical waveguide by the laser as described above, it is necessary to obliquely set an optical axis of the laser or to obliquely arrange the optical waveguide in a laser processing apparatus. For this reason, a laser processing apparatus of a special specification is required, which increases the cost.
Also, since the one recess portion having the inclined surface is sequentially formed by one laser irradiation, the processing time is considerably prolonged in order to form the inclined surfaces in a plurality of core layers of the optical waveguide, which lowers the production efficiency.